Jason Dark is the pseudonym of Helmut Rellergerd ("the least known, best-known German writer", according to Rellergerd himself), a highly prolific author of widely read horror detective fiction in the German language. His fertile and inventive imagination has been favourably compared to that of Sir Arthur Conan Doyle. Helmut Rellergerd was born in 1945 in Dahle, the Sauerland. As Jason Dark, he is a popular and immensely prolific German fiction writer, as well as a best-selling author.